Science & TechnologyS


Bizarro Earth

Cosmic rays at 'space age' high, warns NASA


Press Trust, India
Fri, 11 Dec 2009 15:06 UTC
C
Cosmic Rays
© PTIThe cosmic rays have the potential to harm astronauts, spacecraft.
osmic rays from outer space that can harm astronauts and spacecraft are increasing significantly and now at a "space age" high, NASA researchers have said.

The cosmic ray intensity in 2009 is at a "space age" high, said Richard Mewaldt, one of the scientists analysing data received from NASA's Advanced Composition Explorer spacecraft which is in solar orbit about a million miles from the earth.

"The intensity is actually about 20 per cent higher than solar-minimum periods of recent decades, and if this trend continues, NASA may want to reconsider how much shielding is required if astronauts return to the moon," said Mewaldt from California Institute of Technology.

Cosmic rays are very-high-energy particles that originate in explosions of massive stars elsewhere in the Milky Way galaxy. They travel at nearly the speed of light and strike the Earth from all directions.

People on Earth are not in danger from the rays since the planet is surrounded by a protective shield created by its atmosphere and magnetic field and activity on the sun, which creates a hard-to-penetrate bubble - called the heliosphere - of wind and magnetic field around the solar system.

However, there has been a lull in solar activity since around 2007 and research shows that when solar activity goes down then natural shielding is weakened and more cosmic rays reach Earth.
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Telescope

Scientists observe super-massive black holes using Keck Observatory in Hawaii

Gail Gallessich
University of California - Santa Barbara
Thu, 10 Dec 2009 20:52 UTC
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© M. Kishimoto, MPIfRUKIRT infrared images of the four target galaxies show them in near-infrared color, where the images at different infrared wavelengths are assigned to represent red, green and blue colors. Observations with the Keck Interferometer have resolved the inner structure of the bright nucleus in all the four galaxies. The inferred ring-like structure obtained for NGC 4151 at the top-left is depicted in the top-right panel. The ring radius is 0.13 light years, corresponding to an extremely small ~0.5 milli-arcsecond angular size on the sky. The distance to each galaxy is indicated in million light-years, together with the redshift (z) of each galaxy.
An international team of scientists has observed four super-massive black holes at the center of galaxies, which may provide new information on how these central black hole systems operate. Their findings are published in December's first issue of the journal Astronomy and Astrophysics.

These super-massive black holes at the center of galaxies are called active galactic nuclei. For the first time, the team observed a quasar with an active galactic nucleus, as part of the group of four, which is located more than a billion light years from Earth. The scientists used the two Keck telescopes on top of Mauna Kea in Hawaii. These are the largest optical/infrared telescopes in the world.

The team also used the United Kingdom Infrared Telescope (UKIRT) to follow up the Keck observations, to obtain current near-infrared images of the target galaxies.
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Magnify

Scientists Hear Cell Conversation For First Time


Medical News Today
Thu, 10 Dec 2009 12:00 UTC
A cutting edge technique that allows scientists to monitor communication between cells could transform the way laboratory medical experiments are conducted. The method is likely to make laboratory studies of cancers and other human diseases, and assessment of new drugs to target them, more accurate.

The study was completed by Dr Rune Linding, head of the Cellular and Molecular Logic Team at The Institute of Cancer Research (ICR) in the UK, along with UK and Canadian-based colleagues. The research is published in the latest edition of the journal Science.

Dr Linding says that understanding communication between cells is crucial, as many cancers and other diseases are caused by a breakdown in communications systems.
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Magnify

DNA Sheds New Light on Horse Evolution


ScienceDaily
Thu, 10 Dec 2009 07:00 UTC
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© University of AdelaideBones of a new species of the hippidion horse, discovered in South America.
Ancient DNA retrieved from extinct horse species from around the world has challenged one of the textbook examples of evolution -- the fossil record of the horse family Equidae over the past 55 million years.

The study, published in the Proceedings of the National Academy of Sciences, involved an international team of researchers and the Australian Centre for Ancient DNA (ACAD) based at the University of Adelaide.

Only the modern horse, zebras, wild asses and donkey survive today, but many other lineages have become extinct over the last 50,000 years.

ACAD Director Professor Alan Cooper says despite an excellent fossil record of the Equidae, there are still many gaps in our evolutionary knowledge. "Our results change both the basic picture of recent equid evolution, and ideas about the number and nature of extinct species."
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Telescope

Some Black Holes May Actually Be "Quark Stars"

Dan Vergano
USA Today
Mon, 07 Dec 2009 14:57 UTC
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© NASADust disks that surround supposed black holes, such as the one circling giant star M33-X7 in this artist's representation, could be orbiting so-called quark stars.
Think black holes are strange? Understandable, considering these powerhouses of the universe (many times heavier than our sun) are collapsed stars with gravity so strong that even light cannot escape their grasp.

But maybe they're not "strange" enough, some astrophysicists suggest.

"Stellar" black holes, ones only a few times heavier than the sun, may actually be something even weirder called a quark star, or "strange" star.

A physics team led by Zoltan Kovacs of the University of Hong Kong sizes up the issue in the current Monthly Notices of the Royal Astronomical Society. Quark stars are only theoretical right now, but "the observational identification of quarks stars would represent a major scientific achievement," Kovacs says.

If quark stars exist, it could prove a theory that normal matter - the stuff of people, planets and stars - isn't stable and could help explain the existence of the "dark matter" that fills much of the universe.
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Eye 2

T. Rex Precursor Suggests Dinosaurs Originated in South America

Dan Vergano
USA Today
Thu, 10 Dec 2009 14:33 UTC
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© Jorge GonzalezTawa hallae, a newly unveiled Triassic, carnivorous dinosaur, "helps us reconstruct the origins of all the most primitive dinosaurs, suggesting they were likely located in South America," says Sterling Nesbitt of the American Museum of Natural History.
Discovery of a primitive precursor to Tyrannosaurus Rex, some 215 million years old, points to a South American origin for dinosaurs, paleontologists reported Thursday.

In the journal Science, a team led by Sterling Nesbitt of the American Museum of Natural History in New York, unveils Tawa hallae, found in a fossil bone bed near New Mexico's Ghost Ranch, made famous by the artist Georgia O'Keefe. Nesbitt's team named the creature, a 6.5-foot-long meat-eating precursor to T. Rex, after a Pueblo sun god and the fossil collector Ruth Hall.

"Tawa helps us reconstruct the origins of all the most primitive dinosaurs, suggesting they were likely located in South America," Nesbitt says. The dinosaur, "probably ate anything he got his hands on," he adds.
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Magnet

Electromagnetic Fields as Cutting Tools


ScienceDaily
Thu, 10 Dec 2009 00:00 UTC
The bodywork on motor vehicles must be sufficiently stable, but processing the high-strength steels involved -- for example punching holes in them -- can prove something of a challenge. A new steel-cutting process will save time, energy and money in the future.

Squealing tires and the crunch of impact -- when an accident occurs, the steel sheets that form a motor vehicle's bodywork must provide adequate impact protection and shield its passengers to the greatest extent possible. But the strength of the steels that are used throw up their own challenges, for example when automobile manufacturers have to punch holes in them for cable routing.

Struggling to pierce the hard steel, mechanical cutting tools rapidly wear out. And because they also leave some unwanted material on the underside of the steel (burr, as the experts call it), additional time has to be spent on a finishing process. One possible alternative is to use lasers as cutters, but they require a great deal of energy, which makes the entire process time-consuming and costly.
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Sherlock

Ancient Maya King Shows His Foreign Roots

Bruce Bower
Science News
Wed, 09 Dec 2009 16:17 UTC
Dynastic founder may have been installed by kingdom to the north

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© Early Copán Acropolis Program, U. of Penn. MuseumA tomb excavated at Copán, ancient capital of a Maya state, contains the bones of the site’s first king, researchers say.
A man's skeleton found atop a stone slab at Copán, which was the capital of an ancient Maya state, contains clues to a colonial expansion that occurred more than 1,000 years before Spanish explorers reached the Americas.

The bones come from K'inich Yax K'uk' Mo', or KYKM for short, the researchers report in an upcoming Journal of Anthropological Archaeology. KYKM was the first of 16 kings who ruled Copán and surrounding highlands of what is today northern Honduras for about 400 years, from 426 to 820, say archaeologist T. Douglas Price of the University of Wisconsin - Madison and his colleagues. KYKM's bone chemistry indicates that he grew up in the central Maya lowlands, which are several hundred kilometers northwest of Copán.

Along with inscriptions at Copán, the new evidence suggests that the site's first king was born into a ruling family at Caracol, a powerful lowland kingdom in Belize. KYKM probably spent his young adult years as a member of the royal court at Tikal, a Maya kingdom in the central lowlands of Guatemala, before being sent to Copán to found a new dynasty at the settlement there, Price's team proposes.
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Sherlock

Ancient Tablets Decoded; Shed Light on Assyrian Empire

Brian Handwerk
National Geographic News
Wed, 09 Dec 2009 10:00 UTC
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© University of AkronAncient clay tablets (such as the one pictured) inscribed with cuneiform script, a type of ancient writing once common in the Middle East, have been found in southeastern Turkey.
Meticulous ancient notetakers have given archaeologists a glimpse of what life was like 3,000 years ago in the Assyrian Empire, which controlled much of the region between the Mediterranean Sea and the Persian Gulf.

Clay tablets inscribed with cuneiform, an ancient script once common in the Middle East, were unearthed in summer 2009 in an ancient palace in present-day southeastern Turkey.

Palace scribes jotted down seemingly mundane state affairs on the tablets during the Late Iron Age - which lasted from roughly the end of the ninth century B.C. until the mid-seventh century B.C.

But these everyday details, now in the early stages of decoding, may open up some of the inner workings of the Assyrian government - and the people who toiled in the empire, experts say.
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Telescope

Saturn's Mysterious Hexagon Emerges from Winter Darkness


ScienceDaily
Wed, 09 Dec 2009 11:00 UTC
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© NASAA still from a movie from Cassini, made possible only as Saturn's north pole emerged from winter darkness, showing new details of a jet stream that follows a hexagon-shaped path and has long puzzled scientists.
After waiting years for the sun to illuminate Saturn's north pole again, cameras aboard NASA's Cassini spacecraft have captured the most detailed images yet of the intriguing hexagon shape crowning the planet.

The new images of the hexagon, whose shape is the path of a jet stream flowing around the north pole, reveal concentric circles, curlicues, walls and streamers not seen in previous images. Images and the three-frame animation are available here, here, and here.

The last visible-light images of the entire hexagon were captured by NASA's Voyager spacecraft nearly 30 years ago, the last time spring began on Saturn. After the sunlight faded, darkness shrouded the north pole for 15 years. Much to the delight and bafflement of Cassini scientists, the location and shape of the hexagon in the latest images match up with what they saw in the Voyager pictures.
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